Improvement in sewing machines



2 Sheets-Sheets 1'. W. B. BARTRAM.

Sewing Machine.

No. 60,669; Patented Jan. 1, 1867.

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' w. B. BARTRAM.

Sewing Machine.

Patented Jan. 1,1867.

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TO ALL WHOM IT MAY CONCERN:

Be it known that I, WALKER B. BARTRAM, of Danbury, in the county ofFairfield, and State of Connecticut, have invented a new and usefulImprovement in Sewing Machines; and I do hereby declare the following tobe a full, clear, and exact description of the same, reference being hadto the accompanying drawings, in whicln...

Figure 1 is a side elevation of my machine.

Figure 2 is a front elevation of the same;

Figure 3 is a vertical transverse section through the needle slot.

Figure 4 is an elevation of the needle-driving eccentric. I Figure 5represents a modified arrangement for operating the looping hook.

' The sewing machine presented in this application relates to that classof sewing machines which employ but asingle thread, though many of itsfeatures are equally applicable to any other class of sewing machines.My invention consists, first, in placing the looping hook so that itmoves in a plane at right angles to the direction of the feed movement,and so timing the movements of said hook and the needle that they willoperate'properly in connection with each other, without regard to thedirection of the motion of the driving-wheel; second, in tho vmanner oftightening or slacking the driving belt by moving the machine itself toor from the driving-wheel;

third, in the mode of procuring the desired tension; fourth, in themanner of constructing the-driving eccentric;-

fifth, in. the construction and arrangementof the feed.

That. others may understand the construction and operation of mymachine, I will particularly describe it.

A is the frame of the machine, to which all the working parts areattached. The driving shaft B passes through suitable boxes'at the frontandrear portion of the frame. At the rear end of the shaft B, isthedriving pulley andeccentric, C, which receives motion from thedriving-wheel D, by means 'of a belt,- -as is usual. The loopinghook andthe feeding mechanism receive their movements from cam or crank devices,situated at the front end of the shaft B. The looping hook E is, inshape, substantially as shown in fig. 1; it is hung upon a. pivot orshaft, the axis of which is parallel with the line of movement of thefeeding dog. As the needle is actuated by an eccentric upon the end ofthe same shaft, B, it is easy to so time the hook and needle that theywill move properly in respect to each other, without regard .to thedirection in which the driving mechanism moves. To do this it' isnecessary, for instance, to set the eccentric which drives the needle atthe extremity of its throw, when the needle is entirely depressed, andto set the mechanism which operates the hook so that, at the samemoment,'it shall be entirely thrown back. The parts must also be soarranged that from these two points the movements will be exactly thesame, whether the shaft B revolves backward or forward. From this point,as the shaft revolves, the, needle rises, leaving a slight loop ofthread at the side. Through this loop the hook E passes as it is thrownforward, retaining the thread as the needle rises out of the cloth, andholding'the loop until the needle passes through it at the next stroke.The position of the hook E, and the direction of its stroke, renders theformation of the stitch the same, whichever way the cloth may'move, Thiscannot .be the case if the hook moves in a plane parallel with the planein which the feed moves, for thereason that the loop will slip from thehook a little sooner when the cloth moves in one direction than when itmoves in the other; and the slightest inequalityof operation in thatrespect will spoil the operation of the machine. The feeding mechanismis constructed with teeth, having equal angles on each side of thepoints, so that thecloth will be pierced and moved with equal facilityin either direction. In this machine the feeding dog, F, has arectilinear motion only, and the cloth is freed from the teeth of thedog by the work-lifter, G, which is caused .5 i up t the proper moment,and raising the cloth from the feeding dog, retains it so until the doghas been withdrawn,

and is prepared for another stroke. The work-lifter G is caused toriseand fall by a cam, H, on the end of the driving shaft B. In thisapplication, the feeding dog is represented as being operated by aneccentric pin, I, set in thc front end of the shaft B. Said pin lieswithin a tapering notch in the side of thelarm J, which is pivoted to-the feeding dog at a, as shown. The notch referred to is made withinclined or tapering sides, so that it is wider at the lower than at theupper end. The pin I quite fills the notch at the narrow end, and whenin that position, the arm J, and the feeding dog F, are pushed back andforth, at every revolution, a distance equal to the throw of theeccentric pin; but when, by means of the screw K, the arm J is inclined,so that the pin I lies inthe wider part of the notch, then the arm Jwill be moved only through a distance equal to the dilference betweenthe width of the notch at that point and-the throw of the eccentric pin.In the first-named position, the longest stitch within the capacity ofthe machine will be produced, and in the other case, the feed movementmay be reduced to nothing. Between these two all gradations of lengthmay be attained by regulating the position. of the notch over the pin I,and this may be controlled by the screw K, or by any other of thewelllcnown mechanical expedients adapted'to such uses. In fig. 1, thehook E is represented as actuated by an arrangement of a compound lever,receiving motion from a cam on the forward end of the driving shaft B,but I consider the devices represented in fig. 5 as preferable for thepurpose. They represent the construction which is adopted in practice,and for which I design to make application for Letters Patent at afuture time. A brief.

reference to them is, however, inserted here, as not out of plaice.Thelooping hook E is mounted on a tumbling shaft, 6, through which,also, a pin, 6, is placed, at some little distance from the hook E. Uponthe shaft e is placed a sleeve, 0, which is provided with a diagonalslot, f, for the reception of the pin 12. Now. it will appear evidentthat if the said sleeve is moved back and forth, in the direction of theaxis of the tumbling shaft, without being permitted to rotate on saidaxis, the diagonal slotf, and pin 6, will cause the tumbling shaft andhook E to rotate a distance proportionate to the length and angle of theslot f. This motion of the sleeve is produced by a link, g, and aneccentric pin or crank at the endof the shaft B. The driving-wheel, L,has an eccentric groove turned in its face, and into this groove isloosely fitted the ring M. The pin, N, at the rear end of the needlearm, projects loosely into a suitable hole in the face of this ring, M,and prevents it from revolving on the axis of the driving shaft 13, withthe wheel L. As the driving-wheel L revolves upon its axis, the piii Nrises and falls, influenced by the walls of the eccentric groove, justas though the ring M was not present; the ring, however, serves to fillthe groove, and prevent the access of dust and dirt, and also toincrease the ampunt' of wearing surface, and therefore increase thedurability of the machine. This is a point of great importance, fontherelative action of the various parts of a sewing machine requires suchnice adjustment, that the slightest enlargement of the orifice by wear,or the slightest decrease of the size of a pin from the same cause, mayproduce the most important diilereuces in the timing'and movements ofthe stitching apparatus. The tension 0 is a cylinder, within which thespool is placed, either upon a spool pin, or loosely. The thread ispassed through a small hole in the side of this cylinder, and passedonce or twice around it before being led to the'guide loopsPu Thecylinder may be revolved on its axis to increase or diminish thetension, thereby causing the thread to traverse a greater or lessdistance on its surface. It'- is proposed to construct these cylindersof glass, as presenting facilities for ornamentation, and an excellentsurface for the purpose, though any'otlier suitable material may beemployed. Atmospheric or other causes will frequentlyproduceelongationor contraction of the belt which communicates motion to the machine, andthe common way of remedying this difliculty is taking up or letting outthe belt. To remove the difiiculty of correcting this inequality, I haveplaced the screw R, and its thumbnut, beneath my frame A. The screwpasses through a slot in the table, which permits the machine to bemoved sideways so as to increase or diminish the distance between thecentres of the wheels C andD'. The thumb-nut and screw R clamp themachine firmly to the table at any point desired. By these means theadjustment of the belt is made very quickly, and with the utmost nicety.V

Having described my invention, what I claim as new, and desire to secureby Letters Patent is- 1. The looping hook E, when arranged in. a sewingmachine having areversible feed, so as to move in aplane I at rightangles to the lineof feed, and so timed to the movement of the needlethat the two will operate in proper relation to each other, withoutregard to the direction in which the feed is moving.

2. The combination of the driving-wheel D and pulley G of a sewingmachine, when they are arranged so that the distance betweenthem may bevaried by sliding the machine sideways upon its table, and securing itby the devices shown.

3. The adjiistable tension cylinder 0, constructed and operatingsubstantially as set forth.

4. The combination of the eccentric groove in the pulley L, the ring Mfitted loosely in the said groove, and the pin N, through which theneedle arm is actuated.

5. In combination with a rectilinear feeding dog of a sewing machine,the tapering notched lever J, and eccentric pin I, substantially as andfor the purpose set forth.

W. B. BARTRAM.

Witnesses:

W. F. TAYLOR, A. G.,Gsossr.

